This invention relates generally to locks, and more particularly concerns a lock to prevent casual theft or pilferage from containers which hold items of small value.
Containers such as paper product dispensers, suitcases, carrying cases, drawers, and cabinets may be situated in public places where such containers if not locked, would be subjected to consistent and annoying casual theft and pilferage even though the contents of such containers generally are not of great value. Consequently, it is desirable to have some sort of lock for such containers in order to discourage casual theft or pilferage. In general, such containers themselves are made of plastic and will not hold up to serious assault in any event. Therefore, there is no need to design a lock which will be more indestructible than the containers themselves.
A lock for such containers, which are made of plastic and contain items of small value, should be easy to operate so that authorized personnel with an appropriate key can easily open and service such containers as in the case of toilet paper dispensers. The lock, however, should not be easily opened or damaged by means of ordinary tools such as a screwdriver, knife or the like which may be readily available to unauthorized personnel.
In that regard, a lock for a toilet paper dispenser is the subject of Ridgewell et al. U.S. Pat. No. 4,500,120 assigned to a subsidiary of the assignee of the present invention. The lock disclosed in the Ridgewell et al. patent is designed to prevent casual theft from containers which hold items of small value. The Ridgewell et al. lock includes a hasp on one wall of the container which engages a latch at one end of a release spring. The other end of the release spring is attached to a second wall on the other half of the container by means of a screw. A rotatable cam having a generally triangular shaped cam surface is mounted for rotation between the two sides of the release spring so that the latch can be spread to disengage the hasp when the key turns the cam. The cam profile and the release spring are designed so that a cam can be rotated to a point at which the cam is wedged between the two halves of the release spring so that the release spring remains open. In other words, the release spring will not cause the cam to rotate back to its initial position thereby closing the lock once rotational force is removed from the key. Therefore, unless the operator specifically acts to rotate the cam back to its original position, the dispenser when closed will not be locked. The key hole and the mounting screw for the release spring are offset so that any downward axial force exerted by the operator on the key tends to push the release spring away from the wall to which it is mounted by the screw. Because of the offset, a lever action is created which can cause the release spring to break away from the mounting screw, thereby rendering the lock inoperable. Moreover, the rotatable cam has a single slot key hole which invites a person to try to force the lock with any number of readily available objects, such as screwdriver, pocket knife, or the like. When the lock is forced with a screwdriver, there is a great chance of damage to the dispenser and the lock.